Wouldn't it be great to have other interesting bosses of each planet? Like some sort of king krake that has a 0.05 chance to spawn on Lillith every day or a massive bat that has a 0.33' chance to spawn on Umbra if you've gotten a cumulative total of 50% defense (like 25% slash, 10% blunt, 5% piercing, 15% magic = 55%, meaning it can spawn) and they'll drop some cool gear too? This will probably be hard to make, but the whole game of junk jack is underground, there is literally nothing to do on the surface unless your character too weak to go underground or you need to farm some mob.